Global Patent Index - EP 1164763 A2

EP 1164763 A2 20011219 - Predistortion in a 12/4 star QAM modulator

Title (en)

Predistortion in a 12/4 star QAM modulator

Title (de)

Vorverzerrung in einem 12/4-Stern-QAM-Modulator

Title (fr)

Prédistortion dans un modulateur de signaux MAQ en forme d'étoile 12/4

Publication

EP 1164763 A2 20011219 (EN)

Application

EP 01112840 A 20010530

Priority

US 59332800 A 20000614

Abstract (en)

Methods and devices for predistorted 12/4 Quadrature Amplitude Modulation that compensate for distortion from a nonlinear element. Modulator input bits are mapped (40) to a plurality of nonreturn-to-zero (NRZ) modulator control bit (20-30). The mapping is determined by desired points on a 12/4 QAM constellation. At least one phase shift device (4, 6) receives an input signal and at least one of the plurality of modulator control bit. At least two quaternary phase shift keying (QPSK) devices (8, 10) receive phase shifted signals from at least one phase shift device. Each of at least two QPSK devices receives at least one of the plurality of NRZ symbols. An attenuator (32) that attenuates a first QPSK signal outputted from a first QPSK device of the at least two QPSK devices. A summer (34) sums the attenuated first QPSK signal with a second QPSK signal. The second QPSK signal is outputted from a second QPSK device of the two QPSK devices. The summer outputs a predistorted 12/4-QAM signal. The plurality of modulator control bit control the at least one phase shift devices and the two QPSK modulators to achieve the desired points on the 12/4 QAM constellation. <IMAGE>

IPC 1-7

H04L 27/36

IPC 8 full level

H04B 3/04 (2006.01); H04L 27/01 (2006.01); H04L 27/36 (2006.01)

CPC (source: EP US)

H04L 27/368 (2013.01 - EP US)

Designated contracting state (EPC)

DE FR GB

DOCDB simple family (publication)

EP 1164763 A2 20011219; EP 1164763 A3 20041201; EP 1164763 B1 20081217; DE 60136994 D1 20090129; JP 2002158728 A 20020531; JP 3527716 B2 20040517; US 6674811 B1 20040106

DOCDB simple family (application)

EP 01112840 A 20010530; DE 60136994 T 20010530; JP 2001179809 A 20010614; US 59332800 A 20000614